CN112654451A

CN112654451A - Coated cutting tool and cutting tool

Info

Publication number: CN112654451A
Application number: CN201980057977.8A
Authority: CN
Inventors: 胜间忠
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2018-09-05
Filing date: 2019-09-03
Publication date: 2021-04-13
Anticipated expiration: 2039-09-03
Also published as: WO2020050259A1; JPWO2020050259A1; JP7142097B2; CN112654451B; US11992883B2; US20210187624A1; DE112019004458T5

Abstract

The coated cutting tool of the present invention has a substrate having a first face and a coating film on the first face. The matrix has a hard phase containing tungsten carbide particles, and a binder phase containing at least one of cobalt and nickel. Island portions having an equivalent circle diameter of 10 μm or more are scattered on the first surface, and the island portions contain 70 area% or more of the binder phase. The coating layer has a first layer containing a titanium compound on the first surface and a second layer containing alumina on the first layer. The coating layer has a plurality of pores arranged in a direction along a boundary between the first layer and the second layer in the first layer in a cross section orthogonal to the first surface. An average value of widths of the voids in a direction along the interface is smaller than an average value of intervals of adjacent voids.

Description

Coated cutting tool and cutting tool

Technical Field

The present invention relates to a coated tool for cutting machining.

Background

As a coated tool used for cutting such as turning and milling, for example, a coated tool described in patent document 1 is known. As shown in fig. 2 of patent document 1, for example, the cutting tool disclosed in patent document 1 discloses the following technique: the bonding strength between the substrate and the coating layer is improved by providing a sea-island structure in which a plurality of binder phase aggregated portions, in which cobalt (Co) and nickel (Ni) are aggregated, are scattered on the surface of the substrate.

Patent document 2 describes a coated tool in which a coating layer including a layer containing a titanium (Ti) compound (titanium compound layer) and a layer containing alumina (Al) is formed on the surface of a substrate made of cemented carbide or the like₂O₃) Layer (aluminum oxide layer). In the coated cutting tool described in patent document 2, it is described that a plurality of pores are formed in the interface between the titanium compound layer and the alumina layer, and the impact relaxation effect can be obtained by the plurality of pores.

As described in these patent documents, in the coated cutting tool, measures are taken to improve the bondability between the substrate and the coating layer and to reduce the impact effect of the coating layer.

Documents of the prior art

Patent document

Patent document 1: WO2006/104004

Patent document 2: japanese patent laid-open publication No. 2015-182209

Disclosure of Invention

The coated cutting tool of the present invention has a substrate having a first surface, and a coating film on the first surface. The matrix has a hard phase containing tungsten carbide particles and a binder phase containing at least one of cobalt and nickel. And, on the first surface, there are scattered island portions having an equivalent circle diameter of 10 μm or more, the island portions containing 70 area% or more of the binder phase. The coating layer has a first layer containing a titanium compound on the first surface and a second layer containing alumina on the first layer. The coating layer has a plurality of pores arranged in a direction along a boundary between the first layer and the second layer in the first layer in a cross section orthogonal to the first surface. An average value of widths of the voids in a direction along the interface is smaller than an average value of intervals of adjacent voids.

The cutting tool of the present invention comprises: a shank which has a bar shape extending from a first end to a second end and has a blade groove located on the first end side; and the coating cutter is positioned in the cutter groove.

Drawings

Fig. 1 is a perspective view showing a coated cutting tool of the present invention.

Fig. 2 is a cross-sectional view of the coated cutting tool shown in fig. 1, taken along the line a-a.

Fig. 3 is an enlarged view of the vicinity of the coating layer of the coated cutting tool shown in fig. 2.

Fig. 4 is an enlarged view showing an example of the region B1 shown in fig. 3.

Fig. 5 is an enlarged view showing another example of the region B1 shown in fig. 3.

Fig. 6 is a plan view showing the cutting tool of the present invention.

Fig. 7 is an enlarged view of the region B2 shown in fig. 6.

Detailed Description

The coated cutting tool 1 of the present invention will be described in detail below with reference to the drawings. However, for convenience of explanation, the drawings referred to below simply show only main members necessary for explaining the embodiment. Therefore, the coated cutting tool can be provided with any structural member not shown in the respective drawings to which reference is made. The dimensions of the members in the drawings do not faithfully represent the actual dimensions of the structural members, the dimensional ratios of the members, and the like.

< coated cutting tool >

As shown in fig. 1 and 2, the coated cutting tool 1 of the present invention includes a substrate 3 and a coating 5. The base body 3 has a first face 7 (upper face in fig. 2), a second face 9 (side face in fig. 2) adjacent to the first face 7, and a cutting edge 11 located at least in part of a ridge line where the first face 7 and the second face 9 intersect.

In the example shown in fig. 1, the base 3 has a square plate shape, and the first surface 7 has a square shape. Thus, the number of second faces 9 is 4. At least a part of the first surface 7 is a rake surface region, and at least a part of the second surface 9 is a relief surface region. The shape of the base 3 is not limited to the quadrangular plate shape, and the first surface 7 may be a triangular shape, a pentagonal shape, a hexagonal shape, or a circular shape, for example. The substrate 3 is not limited to a plate shape, and may be, for example, a columnar shape.

The matrix 3 contains, for example, 5 to 10 mass% of at least one of cobalt and nickel, and further contains a hard phase composed of WC, a carbide, a nitride, and a carbonitride of a metal. From the viewpoint of enhancing the hardness, the average particle diameter of these hard phases may be 3 μm or less, or may be 1 μm or less.

The matrix 3 has a plurality of binder phase aggregated portions aggregated by a binder phase dispersed on the surface. The binder phase aggregation portion is also referred to as an island portion, and the other portions of the island portion are referred to as sea-island structures on the surface. The binder phase aggregation portion is a portion containing 70 area% or more of the binder phase with respect to the area of a region where a hue difference is observed in a plan view or a cross-sectional view using a Scanning Electron Microscope (SEM) or the like. When the portion where the hue difference was confirmed was the binder phase aggregated portion (island portion), the proportion of the binder phase was less than 70 area% in the region in the sea other than the binder phase aggregated portion.

The equivalent circle diameter of the binder phase aggregation part is 10 μm or more when viewed from a direction perpendicular to the first surface 7 as the surface of the substrate 3. The equivalent circle diameter may be 50 μm or more. The circle-equivalent diameter may be 300 μm or less. The surface of the substrate 3 preferably has a binder phase aggregation portion with an area ratio of 10 to 70%. The substrate 3 having the binder phase aggregated portion in the range of the equivalent circle diameter is excellent in the bondability between the substrate 3 and the coating layer.

The equivalent circle diameter and the area ratio of the binder phase aggregation part can be analyzed by image analysis software after a reflected electron image is taken by SEM, for example. When the difference in color tone between the binder phase aggregates and other parts is emphasized during imaging or by using image analysis software, analysis is facilitated. In addition, a device such as WDS that can map each type of element may be used. In any case, it is preferable that, for example, the enlargement ratio is adjusted so that a plurality of binder phase aggregation parts are accommodated in 1 picture, and the picture is taken, and the circle-equivalent diameter and the area ratio are calculated using image analysis software. The area to be measured is preferably 1mm × 1 mm. In addition, the number of binder phase aggregates to be measured is preferably at least 10 or more. When the substrate 3 has the through-holes 23 and the surface of the substrate 3 is exposed to the through-holes 23, the size and area of the binder phase aggregation part may be determined by regarding the surface of the through-holes 23 as the surface of the substrate 3. When the surface of the substrate 3 is not exposed, the size and area of the binder phase aggregation part may be determined after the coating film 5 is removed.

The coating 5 is located on at least a first side 7 of the substrate 3. The coating 5 may be provided only on the first surface 7, or may be provided on a surface other than the first surface 7 of the substrate 3. In the example shown in fig. 2, the coating 5 is also located on the second side 9 in addition to the first side 7. The coated tool 1 is provided with the coating 5 in order to improve characteristics such as wear resistance and chipping resistance during cutting.

The substrate 3 may have a through-hole 23 that penetrates the first surface 7 and a surface located on the opposite side of the first surface 7. The through hole 23 can be used to insert a fixing member for fixing the coated cutting tool 1 to the holder. Examples of the fixing member include a screw and a clamp member.

The size of the substrate 3 is not particularly limited, and for example, the length of one side of the first surface 7 is set to about 3 to 20 mm. The height from the first surface 7 to the surface opposite to the first surface 7 is set to be about 5 to 20 mm.

As shown in fig. 3, the coating 5 has a first layer 13 and a second layer 15. The first layer 13 is located on the first face 7 and contains a titanium compound. The second layer 15 is in contact with the first layer 13 and contains alumina (Al)₂O₃). In fig. 3, the binder phase aggregation part is omitted.

In the blade 1 having the binder phase aggregated portion of the present invention, the substrate 3 and the coating 5 are excellent in the bondability.

Examples of the titanium compound contained in the first layer 13 include carbides, nitrides, oxides, carbonitrides, oxycarbides, and oxycarbonitrides of titanium. The first layer 13 may have a structure containing only one of the above compounds, or may have a structure containing a plurality of the above compounds.

The first layer 13 may have a structure containing a titanium compound, and may have a single-layer structure or a structure in which a plurality of layers are stacked. For example, the first layer 13 may have a laminated structure of the titanium nitride layer 17 and the titanium carbonitride layer 19. In the case where the first layer 13 has the titanium nitride layer 17, the bonding force of the base body 3 to the first layer 13 is higher. The titanium nitride layer 17 and the titanium carbonitride layer 19 are mainly composed of titanium nitride and titanium carbonitride, respectively, and may contain other components. The "main component" refers to a component having the largest mass% value as compared with other components.

The coating 5 may be composed of only the first layer 13 and the second layer 15, or may have a layer other than these layers. For example, another layer may be present between the substrate 3 and the first layer 13, or another layer may be present on the second layer 15.

The titanium carbonitride layer 19 may have a structure in which a plurality of regions having different compositions are stacked. For example, the titanium carbonitride layer 19 may have a structure in which a so-called mt (modified temperature) -first region 19a and a so-called ht (high temperature) -second region 19b are stacked.

When the first layer 13 has the first region 19a and the second region 19b, the first layer 13 may further have an intermediate region 19c between the first region 19a and the second region 19 b. The boundaries of the layers and regions can be determined by, for example, observing SEM photographs or Transmission Electron Microscope (TEM) photographs. This determination can be made based on the difference in the ratio of elements constituting each layer, the size of crystals, and the orientation.

Further, as alumina contained in the second layer 15, for example, α -alumina (α -Al) can be mentioned₂O₃) Gamma-alumina (gamma-Al)₂O₃) And kappa-alumina (kappa-Al)₂O₃). In the case where the second layer 15 contains α -alumina, among others, the heat resistance of the coated cutting tool 1 can be improved. The second layer 15 may have a structure containing only one of the compounds described above, or may have a structure containing a plurality of the compounds described above.

The alumina contained in the second layer 15 can be evaluated by analyzing the above-mentioned compounds by X-Ray Diffraction (XRD: X-Ray Diffraction), and observing the distribution of the peak values.

The content ratio of the titanium compound in the first layer 13 and the content ratio of the alumina in the second layer 15 are not limited to specific values. For example, the first layer 13 contains a titanium compound as a main component, and the second layer 15 contains alumina as a main component. The "main component" as used herein means a component having the largest mass% value as compared with other components, as described above.

The first layer 13 may contain a component other than a titanium compound, and the second layer 15 may contain a component other than alumina. For example, when the first layer 13 contains alumina and the second layer 15 contains a titanium compound, the adhesiveness between the first layer 13 and the second layer 15 is improved.

As shown in fig. 4, the coating 5 has voids 21 inside the first layer 13. Specifically, the first layer 13 of the coating 5 has a plurality of pores 21 in a cross section perpendicular to the first surface 7 of the substrate 3, and the plurality of pores 21 are arranged in a direction along the boundary 16 between the first layer 13 and the second layer 15.

In a cross section orthogonal to the first surface 7, an average value of widths w1 of the holes 21 in a direction parallel to the first surface 7 is smaller than an average value of widths w2 of the adjacent holes 21, that is, the first portion X. The coated cutting tool 1 satisfying such a structure can suppress a decrease in strength of the first portion X and can obtain high impact resistance in the hollow 21. Therefore, the effect of reducing the impact by the void 21 can be obtained while suppressing the deterioration of the bondability between the first layer 13 and the second layer 15.

In the evaluation of the average value of the widths w1 of the voids 21 in the direction parallel to the first surface 7, it is not necessary to evaluate the widths w1 of all the voids 21 present in the cross section orthogonal to the first surface 7, and the evaluation may be performed based on the average value of the widths w1 of about 5 to 10 voids 21 arranged in a row in the cross section. For example, a 10 μm square region including the boundary 16 between the first layer 13 and the second layer 15 may be extracted in a cross section perpendicular to the first surface 7, and the width w1 of the hole 21 in the region may be measured. The average value of the width w2 of the first portion X may be evaluated based on the average value of the intervals between the holes 21 arranged in the cross section in an array of about 5 to 10. In addition, in the present invention, an average value may be determined. In any of these cases, the average value of the values is preferably about 5 to 10.

The voids 21 may be present in the first layer 13. For example, the structure may be located not only in the first layer 13 as shown in fig. 4 but also in the first layer 13 and the second layer 15 as shown in fig. 5. In fig. 5, an imaginary line segment along the boundary 16 between the first layer 13 and the second layer 15 is indicated by a one-dot chain line, and the void 21 located in the second layer 15 may be arranged along the boundary 16 between the first layer 13 and the second layer 15.

The arrangement of the voids 21 along the boundary 16 between the first layer 13 and the second layer 15 means that the intervals between the plurality of voids 21 and the boundary 16 between the first layer 13 and the second layer 15 are within ± 20% of the average value thereof.

In the case where the first layer 13 contains titanium carbonitride as a titanium compound and the second layer 15 contains α -alumina as alumina from the viewpoint of heat resistance and durability of the coated tool 1, when the plurality of pores 21 are located in the first layer 13, the durability of the coated tool 1 can be further improved.

This is because titanium carbonitride has low impact resistance although it has high hardness as compared with α -alumina, and the presence of the pores 21 in the first layer 13 can improve the impact resistance of the pores 21 in the first layer 13, and can further improve the durability of the coated cutting tool 1.

The size of the pores 21 is not particularly limited, and may be set to 20 to 200nm, for example. When the size of the void 21 is 20nm or more, the effect of relaxing the impact by the void 21 can be improved. In addition, when the size of the void 21 is 200nm or less, the strength of the first layer 13 is easily maintained. The size of the void 21 is the maximum value of the width w1 of the void 21 in the cross section perpendicular to the first surface 7.

Further, the shape of the void 21 is not particularly limited, but in a cross section orthogonal to the first surface 7, when the width w1 in the direction parallel to the first surface 7 is larger than the height h1 in the direction orthogonal to the first surface 7, in other words, when the average value of the width w1 in the direction parallel to the first surface 7 of the void 21 is larger than the average value of the height h1 in the direction orthogonal to the first surface 7 of the void 21, the ratio of the void 21 can be suppressed and the impact resistance can be further improved. This is for the following reason.

When a workpiece is cut to produce a cut product, a cutting load is easily applied to the coating 5 in a direction perpendicular to the first surface 7. At this time, in the case where the hole 21 has a shape in which the width w1 in the direction parallel to the first surface 7 is larger than the height h1 in the direction orthogonal to the first surface 7, the cutting load can be absorbed over a wide range of the hole 21 without increasing the size of the hole 21 more than necessary. Therefore, the ratio of the voids 21 can be suppressed and the impact resistance can be further improved. The height h1 of the void 21 in the direction orthogonal to the first surface 7 is the maximum value of the height h1 of the void 21 in the direction orthogonal to the first surface 7.

Specifically, when the ratio of the average value of the width w1 of the hole 21 in the direction orthogonal to the first surface 7 to the average value of the height h1 of the hole 21 in the direction parallel to the first surface 7 is 1.2 or more, the cutting load is easily absorbed over a wide range of the hole 21. In addition, when the ratio is 2 or less, the deformation amount of the cavity 21 in the direction orthogonal to the first surface 7 is easily secured, and therefore the cutting load is easily and stably absorbed in the cavity 21.

When Rz is defined as the maximum height of the boundary between the first surface 7 and the second surface 9 in the cross section orthogonal to the first surface 7, when the average value of the heights h1 in the direction orthogonal to the first surface 7 of the pores 21 is smaller than Rz, the durability of the coating layer 5 is easily suppressed from decreasing.

The coated cutting tool 1 according to the invention has a high impact resistance due to the deformation of the first portion X of the first layer 13 between adjacent cavities 21 and of the plurality of cavities 21. Here, when the average value of the widths of the holes 21 in the direction orthogonal to the first surface 7 is smaller than Rz, the imaginary line connecting the adjacent holes 21 is represented by a zigzag shape bent to be larger than the width of the hole 21.

When the imaginary line is represented by the above-described shape, even if a crack is generated in one first portion X, the crack hardly progresses toward the first portion X located adjacent to the first portion X in which the crack is generated. Therefore, the durability of the coating 5 is difficult to be reduced.

In addition, in the cross section orthogonal to the first face 7, even when the average value of the distance d1 from the void 21 to the boundary 16 between the first layer 13 and the second layer 15 is larger than the average value of the width w2 of the first portion X, the durability of the coating layer 5 is less likely to decrease. Note that the distance d1 from the hole 21 to the boundary 16 between the first layer 13 and the second layer 15 is the minimum value of the distance from the hole 21 to the boundary 16.

This is because, in the above case, the distance from the void 21 to the boundary 16 between the first layer 13 and the second layer 15 can be sufficiently secured as compared with the first portion X, and therefore, even if a crack is generated in one first portion X, the crack is hard to reach the boundary 16 between the first layer 13 and the second layer 15. Since the crack is hard to reach the boundary 16 between the first layer 13 and the second layer 15, the bondability between the first layer 13 and the second layer 15 is hard to be reduced.

Voids 21 are located in first layer 13 and are located away from the boundary of first layer 13 and second layer 15. Here, in the case where the average value of the distance d1 from the void 21 to the boundary 16 of the first layer 13 and the second layer 15 is larger than the average value of the height h1 of the void 21 in the direction orthogonal to the first surface 7 in the cross section orthogonal to the first surface 7, the impact resistance in the coating 5 is improved, and the adhesiveness of the first layer 13 and the second layer 15 is difficult to be reduced.

This is because, compared with the size of the void 21, the distance from the void 21 to the boundary 16 of the first layer 13 and the second layer 15 can be sufficiently ensured, and therefore, even in the case where the void 21 is deformed by absorbing the cutting load, the boundary 16 of the first layer 13 and the second layer 15 is not deformed or the deformation amount becomes sufficiently small. Since the boundary 16 between the first layer 13 and the second layer 15 is less likely to be largely deformed, the bondability between the first layer 13 and the second layer 15 is less likely to be reduced.

< manufacturing method >

Next, an example of the method for manufacturing the coated cutting tool of the present invention will be described.

First, a metal powder, a carbon powder, and the like are appropriately added to an inorganic powder selected from carbide, nitride, carbonitride, oxide, and the like of a cemented carbide that can be formed into the matrix 3 by firing, and mixed to prepare a mixed powder.

For example, the tungsten carbide (WC) powder having an average particle size of 1.0 μm or less is 79 to 94.8 mass%, the Vanadium Carbide (VC) powder having an average particle size of 0.3 to 1.0 μm is 0.1 to 3.0 mass%, and the chromium carbide (Cr) powder having an average particle size of 0.3 to 2.0 μm is₃C₂) 0.1 to 3 mass% of a powder,and metal cobalt (Co) having an average particle diameter of 0.2 to 0.6 μm is 5 to 15 mass%, and further mixed with metal tungsten (W) powder or carbon black (C) as required.

Next, in the mixing, an organic solvent such as methanol is added so that the solid content ratio of the slurry becomes 60 to 80 mass%, and an appropriate dispersant is added, and the mixture is pulverized by a pulverizing device such as a ball mill or a vibration mill for a pulverizing time of 10 to 20 hours, whereby the mixture powder is homogenized, and then an organic binder such as paraffin is added to the mixture powder to obtain a mixture powder for molding.

Then, the mixed powder is molded into a predetermined shape by a known molding method such as press molding, cast molding, extrusion molding, and cold isostatic press molding, and then fired in an argon gas of 0.01 to 0.6MPa at 1350 to 1450 ℃, preferably 1375 to 1425 ℃ for 0.2 to 2 hours, and then cooled at a rate of 55 to 65 ℃/min to a temperature of 800 ℃ or less, thereby obtaining the substrate 3.

In the above firing conditions, if the firing temperature is less than 1350 ℃, the alloy cannot be densified and the hardness is reduced, whereas if the firing temperature exceeds 1450 ℃, the WC particles grow and the hardness and strength are reduced. In addition, when the firing temperature is out of the above range, or when the gas atmosphere during firing is less than 0.01MPa or more than 0.6MPa, binder phase aggregated portions are not formed in either case, and the heat release property at the surface of the cemented carbide is lowered. In addition, if the atmosphere during firing is N₂In the gas atmosphere, the binder phase aggregated portion is not formed. When the cooling rate is lower than 55 ℃/min, the binder phase aggregated portions are not generated, and when the cooling rate is higher than 65 ℃/min, the area ratio of the binder phase aggregated portions becomes too large.

If necessary, the surface of the base body 3 may be subjected to a grinding process and a honing process.

Next, the coating 5 is formed on the surface of the substrate 3 by a Chemical Vapor Deposition (CVD) method.

First, the titanium nitride layer 17 (substrate) in the first layer 13 is formedLayer) is formed. In the presence of hydrogen (H)₂) The gas is mixed with 0.5 to 10 vol% of titanium tetrachloride gas and 10 to 60 vol% of nitrogen gas to prepare a first mixed gas used as a reaction gas. Introducing the first mixed gas into the furnace chamber at a gas partial pressure of 10 to 20kPa, and forming a titanium nitride layer 17 at a temperature of 830 to 870 ℃.

Next, the first region 19a in the first layer 13 is formed. A second mixed gas is produced by mixing 0.5 to 10 vol% of titanium tetrachloride gas, 5 to 60 vol% of nitrogen gas, and 0.1 to 3 vol% of acetonitrile gas in hydrogen gas. Introducing the second mixed gas into the furnace chamber at a gas partial pressure of 6 to 12kPa, and forming a film on the first region 19a containing MT-titanium carbonitride at a temperature range of 830 to 870 ℃.

Then, the intermediate region 19c is formed. Mixing 3 to 30 vol% of titanium tetrachloride gas, 3 to 15 vol% of methane gas, 5 to 10 vol% of nitrogen gas, and 0.5 to 5 vol% of carbon dioxide (CO) in hydrogen gas₂) Gas to produce a third mixed gas. Introducing the third mixed gas into the furnace chamber at a gas partial pressure of 6 to 12kPa, and forming a film in the intermediate region 19c having a thickness of about 50 to 300nm at a temperature of 980 to 1050 ℃. The third mixed gas contains carbon dioxide gas, and thereby the hollow holes 21 are formed in the intermediate region 19 c. If the above conditions are set, the following coated cutting tool 1 can be produced: in a cross section orthogonal to first surface 7, an average value of widths w1 of holes 21 in a direction parallel to first surface 7 is smaller than an average value of intervals w2 of adjacent holes 21.

In this case, since the thickness of the intermediate region 19c is as thin as about 50 to 300nm, the voids 21 formed in the intermediate region 19c can be arranged so as to be aligned in a direction along the boundary 16 between the first layer 13 and the second layer 15.

Next, the second region 19b of the first layer 13 is formed. A fourth mixed gas is produced by mixing 1 to 4 vol% of titanium tetrachloride gas, 5 to 20 vol% of nitrogen gas, 0.1 to 10 vol% of methane gas, and 0.5 to 10 vol% of carbon dioxide gas in a hydrogen gas. Introducing the fourth mixed gas into the furnace chamber at a gas partial pressure of 5 to 45kPa, and forming a film of the second region 19b containing HT-titanium carbonitride having a thickness of about 0.3 to 3 μm at a temperature of 950 to 1050 ℃.

Next, the second layer 15 is formed. Setting the film forming temperature to 950-1100 ℃, setting the gas pressure to 5-20 kPa, and mixing 5-15 vol% of aluminum trichloride (AlCl) in hydrogen gas for the composition of the reaction gas₃) Gas, 0.5 to 2.5 vol% hydrogen chloride (HCl) gas, 0.5 to 5.0 vol% carbon dioxide gas, and 0 to 1 vol% hydrogen sulfide (H)₂S) gas to produce a fifth mixed gas. The fifth mixed gas is introduced into the furnace chamber to form the second layer 15.

Thereafter, if necessary, a portion of the cutting edge 11 on the surface of the coating 5 after film formation is polished. When such a grinding process is performed, the workpiece is easily prevented from adhering to the cutting edge 11, and therefore the coated tool 1 having more excellent chipping resistance is obtained.

The above-described manufacturing method is an example of a method for manufacturing the coated cutting tool 1. Therefore, it is needless to say that the coated cutting tool 1 is not limited to the coated cutting tool manufactured by the above-described manufacturing method. For example, a third layer may be formed on the second layer 15.

In the case of producing the coated cutting tool 1 in which the average value of the width w1 in the direction parallel to the first surface 7 of the cross-sectional hollow hole 21 perpendicular to the first surface 7 is larger than the average value of the height h1 in the direction perpendicular to the first surface 7 of the hollow hole 21, it is preferable that the intermediate region 19c is formed to have a thickness of about 50 to 150nm by adjusting the time when the intermediate region 19c is formed.

In the production of the coated cutting tool 1 in which the average value of the distance d1 from the void 21 to the boundary 16 in the cross section orthogonal to the first surface 7 is larger than the average value of the height h1 of the void 21 in the direction orthogonal to the first surface 7, it is preferable that the second region 19b in the first layer 13 is formed to a thickness of about 0.5 to 3 μm after the intermediate region 19c is formed to a thickness of about 50 to 150nm by time adjustment. In the coated cutting tool 1 in which the average value of the distance d1 from the hole 21 to the boundary 16 is larger than the average value of the interval w2 between adjacent holes 21 in the cross section orthogonal to the first surface, it is preferable to form the second region 19b in the first layer 13 so as to be thicker than the average value of the interval w2 between adjacent holes 21.

< cutting tool >

Next, the cutting insert 101 of the present invention will be described with reference to the drawings.

As shown in fig. 6 and 7, the cutting insert 101 of the present invention includes: a shank 105 which is a rod-shaped body extending from a first end (upper in fig. 6) toward a second end (lower in fig. 6) and has a pocket 103 located on a first end side; and the above-described coated cutting tool, which is located in the pocket 103. In the cutting insert 101 of the present invention, the coated insert 1 is attached so that a portion of the ridge line used as a cutting edge protrudes from the tip of the shank 105.

The pocket 103 is a portion to which the coating cutter 1 is fitted, and has a seating surface parallel to the lower surface of the shank 105, and a constraining side surface inclined with respect to the seating surface. The pocket 103 is open at a first end side of the shank 105.

The coating tool 1 is located in the pocket 103. In this case, the lower surface of the coated cutting tool 1 may be in direct contact with the pocket 103, or a sheet may be sandwiched between the coated cutting tool 1 and the pocket 103.

The coating tool 1 is assembled such that a portion of the ridge line used as a cutting edge protrudes outward from the shank 105. The coating cutter 1 is mounted to the shank 105 by means of screws 107. That is, the coated cutting tool 1 is attached to the holder 105 by inserting the screw 107 into the through hole 23 of the coated cutting tool 1, inserting the tip of the screw 107 into a screw hole (not shown) formed in the pocket 103, and screwing the screw portions together.

As the tool shank 105, steel, cast iron, or the like can be used. In particular, steel having high toughness is preferably used for these members.

In the examples shown in fig. 6 and 7, a cutting tool used in so-called turning is exemplified. Examples of the turning include inner diameter machining, outer diameter machining, and grooving. The cutting tool is not limited to use in turning. For example, the coated cutting tool 1 of the above embodiment may be used as a cutting tool used for milling.

Description of reference numerals:

1. coating cutter

3. base

5. coating

7. first face

9. second face

11. cutting edge

13. first layer

15. second layer

16. boundary (boundary of first layer and second layer)

17 titanium nitride layer

19. titanium carbonitride layer

19 a. first region

19 b. second region

19 c.intermediate region

21. hollow hole

23. through hole

101. cutting tool

103. knife groove

105. knife handle

107. set screw.

Claims

1. A coated cutting tool having:

a base body having a first surface; and

a coating film on the first face,

the base body has: a hard phase containing tungsten carbide particles; and a binder phase containing at least one of cobalt and nickel,

wherein the content of the first and second substances,

island portions having an equivalent circle diameter of 10 μm or more are scattered on the first surface, the island portions containing 70 area% or more of the binder phase,

the coating has: a first layer located on the first face and containing a titanium compound; and a second layer which is located in contact with the first layer and contains alumina,

the coating layer has, in a cross section orthogonal to the first surface, a plurality of pores arranged in a direction along a boundary between the first layer and the second layer, and an average value of widths of the pores in the direction along the interface is smaller than an average value of intervals between adjacent pores.

2. The coated cutting tool of claim 1,

the first layer comprises titanium carbonitride and the second layer comprises alpha-alumina.

3. The coated cutting tool of claim 1 or 2,

in a cross section orthogonal to the first surface, an average value of widths of the voids in a direction parallel to the first surface is larger than an average value of heights of the voids in a direction orthogonal to the first surface.

4. The coated cutting tool according to any one of claims 1 to 3,

in a cross section orthogonal to the first surface, an average value of distances from the voids to the boundary is larger than an average value of heights of the voids in a direction orthogonal to the first surface.

5. The coated cutting tool according to any one of claims 1 to 4,

in a cross section orthogonal to the first surface, an average value of distances from the holes to the boundary is larger than an average value of intervals between adjacent holes in a direction parallel to the first surface.

6. A cutting tool, wherein,

the cutting tool has:

a shank which has a bar shape extending from a first end to a second end and has a blade groove located on the first end side; and

the coated cutting tool of any of claims 1-5, located within the pocket.